1. Field of the Invention
The present invention relates to a connecting structure for pieces which are made of hard materials such as metals and the like, for swingably connecting two parts, such as adjacent pieces of a wristband of a watch, a piece and a case of a watch, or a piece and a buckle of a watch (hereinafter called xe2x80x9cpiecexe2x80x9d or xe2x80x9cpieces and the likexe2x80x9d), with a connecting pin.
2. Description of the Related Art
In the wristbands of watches which are constructed by a plurality of metal pieces swingably connected with connecting pins, structures are known in which some pieces can be relatively easily removed by pulling the connecting pins out in order to adjust the length of the wristband to fit the thickness of the user""s wrist.
A structure for connecting adjacent pieces by inserting a hairpin-shaped connecting pin into the overlapped connecting pipes of the adjacent pieces until an engaging portion of the connecting pin deforms, has been proposed as one of the connecting structures for adjusting the length of a wristband. Furthermore, a structure engaging a pipe, which has a C-shaped cross section, between the overlapped connecting pipes and for connecting the pieces by forcibly inserting the connecting pin into the C-shaped pipe, has also been proposed.
However, the structure using the hairpin-shaped connecting pin has problems in that a stable connecting force cannot be obtained, and an undesirable deformation and break may occur as time passes. Furthermore, the structure using the C-shaped pipe has problems in that an additional process for forming the portion which position the C-shaped pipe having a diameter larger than that of the normal connecting pipe in addition to a process for forming the connecting pipe, hence, two processes using two drills with different diameters, are required. Moreover, the structure has additional problems in that the connecting process is laborious and time-consuming.
The present invention is provided to solve the above problems, and an object of the present invention is to provide a connecting structure for the pieces and the like in which a desirable connecting force can be obtained.
Another object of the present invention is to provide a connecting structure for the pieces and the like which offers high operability.
A further object of the present invention is to provide a connecting structure for the pieces and the like which offers high durability.
To achieve at least one of the above objects of the present invention, the present invention provides a connecting structure for swingably connecting two parts such as adjacent pieces and the like of a band and comprises: a plurality of connecting pipes which are provided on the adjacent parts and aligned along the same axis; a connecting pin which is inserted into the connecting pipes; and a C-shaped spring ring which is engaged with an installation groove of said connecting pin in a manner such that the diameter of the spring ring can be reduced; and wherein, together with the connecting pin, the spring ring is inserted into the connecting pipes by reducing the diameter of the spring ring, and fastens the connecting pin to the connecting pipes by enlarging the diameter of the spring ring inside the connecting pipes until the outer surface of the spring ring contacts the inner surface of the connecting pipes.
In this connecting structure, it is preferable that the spring ring is enlarged in a tapered connecting groove which is provided on the inner surface of said connecting pipes, and to fasten the connecting pin to the connecting pipes by engaging the outer part of the spring ring with the connecting groove.
Furthermore, in this connecting structure, it is preferable that at least one or more connecting grooves are provided at an intermediate portion along the longitudinal direction of the aligned connecting pipes.
Furthermore, in this connecting structure, it is preferable that the aligned connecting pipes are composed of a pair of first connecting pipes which are provided at both sides of an end of one of the adjacent parts and a second connecting pipe which is provided at an portion of the other adjacent part, the second connecting pipe is engaged between the pair of first connecting pipes aligned along the same axis, and the connecting groove is provided at one of the end portion of either the first or second connecting pipes which are adjacent to each other, or provided across the end portions of both the first and second connecting pipes which are adjacent to each other.
Furthermore, in the connecting structure of the present invention, a pair of portions which lead to the opening ends of the spring ring may be formed into straight-lined shapes.